Firestop collars serve to seal off wall penetrations for meltable or combustible lines, for instance, pipes or cables, in case of fire. Such a firestop collar has an insert made of an intumescent firestop compound (hereinafter also referred to as an intumescent insert) that can be placed around the line as well as a housing into which the intumescent insert is placed. Upon exposure to extreme heat, for example, in case of fire, the intumescent insert expands, thereby hermetically sealing off the wall penetration, thus preventing propagation of the fire or smoke through the wall penetration. The housing serves to affix and to secure the intumescent insert in its position on the wall penetration so that, in case of fire, it expands in such a way that the wall penetration is completely closed off. Naturally, the firestop collar can also be employed in a penetration through a floor/ceiling. For the sake of simplicity, only the terms wall or wall penetration will be employed below.
German patent application DE 198 52 120 A1, for instance, discloses such a firestop collar. In the circumferential direction, the housing has an interruption so that the housing, together with the intumescent insert placed into it, can be placed around the line. At one circumferential end of the housing, there are tabs that can be pushed into recesses on the opposite end in order to close off the housing in the circumferential direction. This firestop collar is secured in a wall penetration by means of hooks that are hooked into an axial end of the cylinder formed by the housing. These hooks also cover up the tabs on the outside of the housing, thus constituting a securing mechanism for the closure of the housing. On the one hand, this has the drawback that the installation of the collar is very laborious since the circumference of the collar has to be adjusted and the hook has to be secured at the same time. Moreover, the hooks project into the interior and come to into contact with the line, so that they can prevent an unhindered expansion of the intumescent insert.
Another collar is disclosed in international patent application WO 2000/68608 A1. Here, the fastening hooks are pushed into means for holding the hooks on the outer circumference in the axial direction, which has the disadvantage that a secure connection to the fastening hooks is only established in one direction. The housing with the intumescent insert can be slid in the opposite direction against the hooks, so that the collar might be pushed off the hooks.